Fertilizers are used in large volumes of millions of tons per year. They are used all over the globe and throughout most of the year. Some of said fertilizers are salts produced by direct neutralization of an acid and a base. The main examples are ammonium nitrate, which is usually formed by the direct reaction of ammonia and nitric acid, and ammonium phosphates, usually formed in a reaction between phosphoric acid and ammonia. This direct reaction produces neutralization energy. The number of applications for said neutralization energy is limited.
The increasing effects of CO2 emissions and global warming have challenged the industrialized world to find new and better ways to meet the increasing need for energy while reducing greenhouse gases. A treaty recently negotiated in Kyoto, Japan, would require developed-nations to reduce their emissions of greenhouse gases below the levels of 1990 by the year 2010. New strategies for economically controlling the emissions of greenhouse gases are therefore required.
Calcium oxide is manufactured by heating limestone (CaCO3), coral, sea shells, or chalk, which are mainly CaCO3, to drive off carbon dioxide according to the reaction: CaCO3500-600° C.CaO+CO2 This reaction is reversible; calcium oxide will react with carbon dioxide to form calcium carbonate. Yet, the reaction is driven to the right by flushing carbon dioxide from the mixture as it is released. When calcium oxide is mixed with water, it forms calcium hydroxide according to the reaction: CaO+H2OCa(OH)2.
The production of calcium oxide from limestone is one of the oldest chemical transformations produced by man. In Old English, its name is lïm, which is the origin of the modern commercial name for calcium oxide, namely lime. Lime has many properties that make it quite valuable. It is so useful, that it is today produced industrially on a vast scale; over 20 million metric tons were produced in the U.S. in 2000. Some of the disadvantages of this process are as follows: 1. High energy consuming in order to react in these high temperatures 2. Emission of huge amounts of flue gases with high concentration of CO2 (more than 20%) 3. Difficulties in using the emitted CO2 since the flue gases includes SO2 and NOx.
An object of the present invention is to combine the production of (i) a fertilizer selected from the group consisting of ammonium nitrate and ammonium phosphates; and (ii) a concentrated stream of CO2.
Another object is to produce the fertilizer through indirect neutralization of ammonia with an acid selected from the group consisting of nitric acid, phosphoric acid and a combination thereof.
A further object is to utilize the driving force associated with the production of the fertilizer, which is available in large amounts, in many locations and through most of the year, for the production of carbon compounds from carbon dioxide containing gases.
Still another object of the present invention is to reduce air pollution caused by CO2.
Another object of the present invention is to provide an alternative process for the traditional process of calcium oxide/calcium hydroxide production from limestone, an environmentally friendly one, in order to produce calcium oxide with the production of a relatively clean stream of CO2 of commercial value without the need for the high energy consumption presently required in the prior art processes.